Battery life problem with windows 10 mobile insider build 10586.29

[Zulfeqar_AK]

Hello.

I have the latest build installed and facing some problem with battery life. @ 50% it says battery low n switches off the device, on restarting it has 49% battery left and again after some use @ 47 - 45% it again switches off showing battery low warning.

1. I have done reset.
2. Gone back to windows phone 8.1
3. Installed insider build again but same issue.

How to solve this issue?
Please Help.:unhappysweat:

 

[Maurizio Troso]

Dozens of 3ads already opened with explanations. You MUST leave phone plugged when it updates and syncs all its core app, it depends of your country, carrier. wi-fi, and needs 3 / 4 days, same as a pc notebook out of the box. It drains.
Then check all backgrounds apps, log out skype, and so on

 

[Zulfeqar_AK]

Dozens of 3ads already opened with explanations. You MUST leave phone plugged when it updates and syncs all its core app, it depends of your country, carrier. wi-fi, and needs 3 / 4 days, same as a pc notebook out of the box. It drains.
Then check all backgrounds apps, log out skype, and so on

My device(1520) is 14 months old, done all the things you mentioned (background apps, skype, glance brightness etc)
I had the same problem in the previous build too. :/